Although Apple's iPhone software is generally less susceptible to malware than Android, that doesn't mean iOS is completely immune to security issues.

A security researcher has claimed that iOS 7, the current iPhone and iPad operating system, is less secure than iOS 6, making it potentially vulnerable to intruders, CNET reports.

Apple reportedly introduced a change in the kernel of its OS when it introduced iOS 7. This change was meant to improve general security, but Azimuth Security researcher Tarjei Mandt claims it made the software more vulnerable instead.

The kernel essentially refers to the basic level of an operating system. Think of it as the key to a software, since it controls crucial functions such as security and file management.

Apple allegedly made a mistake when it changed the kernel's random number generator, according to Mandt. This random number generator is supposed to produce numbers that are difficult to guess, which would prevent intruders from compromising the OS.

Mandt claims that the generated numbers in iOS 7 are easier to guess than those of iOS 6 since it uses what's referred to as a linear recursion algorithm.

According to Nathan Sportsman, founder and CEO of mobile security firm Praetorian, the issue could be concerning for iOS 7 users. If a hacker found a way to access the kernel, an iPhone owner could be at risk of having his or her phone compromised or infected with malware.

Mandt detailed this alleged security flaw in iOS 7 during his presentation at the Vancouver-based CanSec West conference. Apple hasn't issued a statement in reference to Mandt's claims, but CNET reports that Apple security engineers attending the event approached him after the presentation. Mandt said they "appeared to be kind of concerned."